Python: Select specific parent object automatically on selection change?
I could solve this with an apphandler I registered to. I added a custom property to the model objects to recognize them in there.

def register():
    bpy.app.handlers.scene_update_post.append(addon.scene_update_post)

def unregister():
    bpy.app.handlers.scene_update_post.remove(addon.scene_update_post)

# ---- In the addon module ----

def scene_update_post(scene):
    ob = scene.objects.active
    if ob:
        # Redirect the selection of a model mesh object to the parent track object.
        if ob.is_model:
            scene.objects.active = ob.parent
            ob.parent.select = True
            ob.select = False


This works even when multi selecting objects!